The present invention relates to an exerciser driving mechanism, and more particular to an exerciser driving mechanism with which the feeling of "inoperative pedaling" likely happened to a free wheel upon instantaneously actuating a belt may be eliminated, the gear ratio of driving wheel to free wheel is increased, the contact area of wool felt and flywheel is reduced to enhance the inertial rotating speed of flywheel, while maintaining the expected braking efficiency, thus resulting in an excellent smooth operation.
As people are paying more attention to their health, many indoor body building device have been developed for this purpose, and among them the exerciser is very popular.
It is well known that the exerciser is derived from the principle of bicycle. Referring to FIG. 1 now, an exerciser of the prior art has the pedals 10 attached to a driving wheel 12, the driving wheel 12 can transmit motions to turn a free wheel 16 by means of a chain 14, then a catch member 20 secured in a hole 16 at the free wheel 16 can be applied to make the flywheel 30 driven in one direction.
Again, referring to FIG. 2, the catch member 20 is comprised of an outer shell 22 and an inner shell 24, wherein a plurality of bevel teeth 26 are provided around the inner periphery of the outer shell 22 at one end thereof, the inner shell 24 is secured on the shaft 32 of a flywheel 30, and a snap hook 28 is fitted to the inner shell 24 at an adequate place thereon. A spring (not shown) is built in the snap hook 28 to project the snap hook 28 out of the inner shell 24 normally. But if the spring is pressed, it will make the snap hook 28 lowered. Therefore, as soon as the driving wheel 12 transmits motions in the positive direction to the free wheel 16 through the chain 14, the free wheel will also rotate in the positive direction, then the bevel teeth 26 at the outer shell 22 of the catch member 20 will mesh with the projected snap hook 28 out of the inner shell 24 to drive the flywheel 30, otherwise the snap hook 28 will be pressed by the corresponding face of bevel teeth 26 at the outer shell 22 to prevent it from being driven by the the flywheel 30.
Though the aforesaid driving mechanism does cause any problem in operation, the clearance between two adjacent bevel teeth 26 of the outer shell 22 is likely to cause a feeling of "inoperative pedaling" when one steps on the pedals 10 instantaneously in the positive direction under the condition that the pedals 10 are at a standstill (that is, when the driving wheel 12 and the free wheel 16 are not actuated). Despite of the fact that the clearance between two adjacent bevel teeth 26 is not so wide, the resultant stroke of "inoperative pedaling" will be increased in proposition of the gear ratio of the driving wheel 12 to the free wheel 16, thereby causing the user to feel very uncomfortable. On the other hand, such a feeling of "inoperative pedaling" would also occur upon pedaling at the time when the flywheel 30 is still doing its inertial rotation.
Moreover, the driving mechanism of the prior art uses a wool felt 34 to cover the outer periphery of the flywheel 30 in order to form an adjustable friction drag upon pedaling subject to the contacting condition of the wool felt 34 with the flywheel 30. In the prior art, however, the wool felt 34 usually covers more than one half of the outer diameter of the flywheel 30, that means more than half a turn of the flywheel 30 is subject to the friction drag. Under the situation that the gear ratio of the driving wheel 12 to the free wheel 16 is 3.3:1 to 3.8:1 only, the free wheel 16 is just able to make 3.3 to 3.8 turns at each turn of the driving wheel 12 (the same also applies to the flywheel 30). Therefore, after the turns subject to the friction drag are deducted, the actual turns for inertia positive rotation are greatly reduced, thus leading to an inefficient pedaling which is the reason why one feels uncomfortable upon pedaling an exerciser of the prior art.